Effect of Process Parameters on the Quality and Dimensional Accuracy of TC11 Titanium Alloy Thin-Walled Parts Fabricated by Laser Powder Bed Fusion

To address the challenges of printing quality and dimensional accuracy in the fabrication of TC11 titanium alloy thin-walled components via laser powder bed fusion (L-PBF), this study systematically optimized the L-PBF process parameters and investigated the printing limits of thin-walled structures, providing theoretical and practical guidance for high-precision manufacturing. First, single-factor experiments were conducted to ex-amine the effects of laser power, scanning speed, and hatch spacing on relative density. Subsequently, response surface analysis was performed using a Box-Behnken design to establish a predictive model with relative density and surface roughness as the response variables, enabling multi-objective parameter optimization. Based on the optimized parameters, a series of thin-walled structures with varying wall thicknesses were fabricated, the resulting printing defects were analyzed, and a mathematical model correlating wall thickness with limiting printing height was established. The response surface model exhibited excellent statistical significance, with an F-value of 0.9930 and a p-value of less than 0.0001, indicating a highly reliable fit. The coefficient of determination (R²) of the model was 0.9889, while the adjusted R² and predicted R² were 0.9747 and 0.9146, respectively, confirming the model’s good predictive capability. The optimal process parameters obtained through the model were a laser power of 190 W, a scanning speed of 1100 mm/s, and a hatch spacing of 0.10 mm. Validation experiments conducted under these conditions yielded a deviation of only 5.33% between the predicted and experi-mental comprehensive scores, demonstrating the accuracy of the model. A key achievement of this study is the establishment of a piecewise mathematical model relating wall thickness to limiting printing height: a cubic polynomial for wall thicknesses in the range of 0.2 ≤ t ≤ 0.5 mm and a quadratic polynomial for wall thicknesses in the range of 0.5 ≤ t ≤ 0.8 mm. This model enables accurate prediction of the formability of thin-walled structures.